This repository has been archived by the owner on Oct 21, 2022. It is now read-only.
-
Notifications
You must be signed in to change notification settings - Fork 3
/
Copy pathide-tape.c
2489 lines (2175 loc) · 66.6 KB
/
ide-tape.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/*
* IDE ATAPI streaming tape driver.
*
* Copyright (C) 1995-1999 Gadi Oxman <gadio@netvision.net.il>
* Copyright (C) 2003-2005 Bartlomiej Zolnierkiewicz
*
* This driver was constructed as a student project in the software laboratory
* of the faculty of electrical engineering in the Technion - Israel's
* Institute Of Technology, with the guide of Avner Lottem and Dr. Ilana David.
*
* It is hereby placed under the terms of the GNU general public license.
* (See linux/COPYING).
*
* For a historical changelog see
* Documentation/ide/ChangeLog.ide-tape.1995-2002
*/
#define DRV_NAME "ide-tape"
#define IDETAPE_VERSION "1.20"
#include <linux/module.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/timer.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/jiffies.h>
#include <linux/major.h>
#include <linux/errno.h>
#include <linux/genhd.h>
#include <linux/slab.h>
#include <linux/pci.h>
#include <linux/ide.h>
#include <linux/smp_lock.h>
#include <linux/completion.h>
#include <linux/bitops.h>
#include <linux/mutex.h>
#include <scsi/scsi.h>
#include <asm/byteorder.h>
#include <linux/irq.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <asm/unaligned.h>
#include <linux/mtio.h>
enum {
/* output errors only */
DBG_ERR = (1 << 0),
/* output all sense key/asc */
DBG_SENSE = (1 << 1),
/* info regarding all chrdev-related procedures */
DBG_CHRDEV = (1 << 2),
/* all remaining procedures */
DBG_PROCS = (1 << 3),
};
/* define to see debug info */
#define IDETAPE_DEBUG_LOG 0
#if IDETAPE_DEBUG_LOG
#define debug_log(lvl, fmt, args...) \
{ \
if (tape->debug_mask & lvl) \
printk(KERN_INFO "ide-tape: " fmt, ## args); \
}
#else
#define debug_log(lvl, fmt, args...) do {} while (0)
#endif
/**************************** Tunable parameters *****************************/
/*
* After each failed packet command we issue a request sense command and retry
* the packet command IDETAPE_MAX_PC_RETRIES times.
*
* Setting IDETAPE_MAX_PC_RETRIES to 0 will disable retries.
*/
#define IDETAPE_MAX_PC_RETRIES 3
/*
* The following parameter is used to select the point in the internal tape fifo
* in which we will start to refill the buffer. Decreasing the following
* parameter will improve the system's latency and interactive response, while
* using a high value might improve system throughput.
*/
#define IDETAPE_FIFO_THRESHOLD 2
/*
* DSC polling parameters.
*
* Polling for DSC (a single bit in the status register) is a very important
* function in ide-tape. There are two cases in which we poll for DSC:
*
* 1. Before a read/write packet command, to ensure that we can transfer data
* from/to the tape's data buffers, without causing an actual media access.
* In case the tape is not ready yet, we take out our request from the device
* request queue, so that ide.c could service requests from the other device
* on the same interface in the meantime.
*
* 2. After the successful initialization of a "media access packet command",
* which is a command that can take a long time to complete (the interval can
* range from several seconds to even an hour). Again, we postpone our request
* in the middle to free the bus for the other device. The polling frequency
* here should be lower than the read/write frequency since those media access
* commands are slow. We start from a "fast" frequency - IDETAPE_DSC_MA_FAST
* (1 second), and if we don't receive DSC after IDETAPE_DSC_MA_THRESHOLD
* (5 min), we switch it to a lower frequency - IDETAPE_DSC_MA_SLOW (1 min).
*
* We also set a timeout for the timer, in case something goes wrong. The
* timeout should be longer then the maximum execution time of a tape operation.
*/
/* DSC timings. */
#define IDETAPE_DSC_RW_MIN 5*HZ/100 /* 50 msec */
#define IDETAPE_DSC_RW_MAX 40*HZ/100 /* 400 msec */
#define IDETAPE_DSC_RW_TIMEOUT 2*60*HZ /* 2 minutes */
#define IDETAPE_DSC_MA_FAST 2*HZ /* 2 seconds */
#define IDETAPE_DSC_MA_THRESHOLD 5*60*HZ /* 5 minutes */
#define IDETAPE_DSC_MA_SLOW 30*HZ /* 30 seconds */
#define IDETAPE_DSC_MA_TIMEOUT 2*60*60*HZ /* 2 hours */
/*************************** End of tunable parameters ***********************/
/* tape directions */
enum {
IDETAPE_DIR_NONE = (1 << 0),
IDETAPE_DIR_READ = (1 << 1),
IDETAPE_DIR_WRITE = (1 << 2),
};
struct idetape_bh {
u32 b_size;
atomic_t b_count;
struct idetape_bh *b_reqnext;
char *b_data;
};
/* Tape door status */
#define DOOR_UNLOCKED 0
#define DOOR_LOCKED 1
#define DOOR_EXPLICITLY_LOCKED 2
/* Some defines for the SPACE command */
#define IDETAPE_SPACE_OVER_FILEMARK 1
#define IDETAPE_SPACE_TO_EOD 3
/* Some defines for the LOAD UNLOAD command */
#define IDETAPE_LU_LOAD_MASK 1
#define IDETAPE_LU_RETENSION_MASK 2
#define IDETAPE_LU_EOT_MASK 4
/* Error codes returned in rq->errors to the higher part of the driver. */
#define IDETAPE_ERROR_GENERAL 101
#define IDETAPE_ERROR_FILEMARK 102
#define IDETAPE_ERROR_EOD 103
/* Structures related to the SELECT SENSE / MODE SENSE packet commands. */
#define IDETAPE_BLOCK_DESCRIPTOR 0
#define IDETAPE_CAPABILITIES_PAGE 0x2a
/*
* Most of our global data which we need to save even as we leave the driver due
* to an interrupt or a timer event is stored in the struct defined below.
*/
typedef struct ide_tape_obj {
ide_drive_t *drive;
struct ide_driver *driver;
struct gendisk *disk;
struct kref kref;
/*
* failed_pc points to the last failed packet command, or contains
* NULL if we do not need to retry any packet command. This is
* required since an additional packet command is needed before the
* retry, to get detailed information on what went wrong.
*/
/* Last failed packet command */
struct ide_atapi_pc *failed_pc;
/* used by REQ_IDETAPE_{READ,WRITE} requests */
struct ide_atapi_pc queued_pc;
/*
* DSC polling variables.
*
* While polling for DSC we use postponed_rq to postpone the current
* request so that ide.c will be able to service pending requests on the
* other device. Note that at most we will have only one DSC (usually
* data transfer) request in the device request queue.
*/
struct request *postponed_rq;
/* The time in which we started polling for DSC */
unsigned long dsc_polling_start;
/* Timer used to poll for dsc */
struct timer_list dsc_timer;
/* Read/Write dsc polling frequency */
unsigned long best_dsc_rw_freq;
unsigned long dsc_poll_freq;
unsigned long dsc_timeout;
/* Read position information */
u8 partition;
/* Current block */
unsigned int first_frame;
/* Last error information */
u8 sense_key, asc, ascq;
/* Character device operation */
unsigned int minor;
/* device name */
char name[4];
/* Current character device data transfer direction */
u8 chrdev_dir;
/* tape block size, usually 512 or 1024 bytes */
unsigned short blk_size;
int user_bs_factor;
/* Copy of the tape's Capabilities and Mechanical Page */
u8 caps[20];
/*
* Active data transfer request parameters.
*
* At most, there is only one ide-tape originated data transfer request
* in the device request queue. This allows ide.c to easily service
* requests from the other device when we postpone our active request.
*/
/* Data buffer size chosen based on the tape's recommendation */
int buffer_size;
/* merge buffer */
struct idetape_bh *merge_bh;
/* size of the merge buffer */
int merge_bh_size;
/* pointer to current buffer head within the merge buffer */
struct idetape_bh *bh;
char *b_data;
int b_count;
int pages_per_buffer;
/* Wasted space in each stage */
int excess_bh_size;
/* protects the ide-tape queue */
spinlock_t lock;
/* Measures average tape speed */
unsigned long avg_time;
int avg_size;
int avg_speed;
/* the door is currently locked */
int door_locked;
/* the tape hardware is write protected */
char drv_write_prot;
/* the tape is write protected (hardware or opened as read-only) */
char write_prot;
u32 debug_mask;
} idetape_tape_t;
static DEFINE_MUTEX(idetape_ref_mutex);
static struct class *idetape_sysfs_class;
static void ide_tape_release(struct kref *);
static struct ide_tape_obj *ide_tape_get(struct gendisk *disk)
{
struct ide_tape_obj *tape = NULL;
mutex_lock(&idetape_ref_mutex);
tape = ide_drv_g(disk, ide_tape_obj);
if (tape) {
if (ide_device_get(tape->drive))
tape = NULL;
else
kref_get(&tape->kref);
}
mutex_unlock(&idetape_ref_mutex);
return tape;
}
static void ide_tape_put(struct ide_tape_obj *tape)
{
ide_drive_t *drive = tape->drive;
mutex_lock(&idetape_ref_mutex);
kref_put(&tape->kref, ide_tape_release);
ide_device_put(drive);
mutex_unlock(&idetape_ref_mutex);
}
/*
* The variables below are used for the character device interface. Additional
* state variables are defined in our ide_drive_t structure.
*/
static struct ide_tape_obj *idetape_devs[MAX_HWIFS * MAX_DRIVES];
static struct ide_tape_obj *ide_tape_chrdev_get(unsigned int i)
{
struct ide_tape_obj *tape = NULL;
mutex_lock(&idetape_ref_mutex);
tape = idetape_devs[i];
if (tape)
kref_get(&tape->kref);
mutex_unlock(&idetape_ref_mutex);
return tape;
}
static void idetape_input_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
unsigned int bcount)
{
struct idetape_bh *bh = pc->bh;
int count;
while (bcount) {
if (bh == NULL) {
printk(KERN_ERR "ide-tape: bh == NULL in "
"idetape_input_buffers\n");
ide_pad_transfer(drive, 0, bcount);
return;
}
count = min(
(unsigned int)(bh->b_size - atomic_read(&bh->b_count)),
bcount);
drive->hwif->tp_ops->input_data(drive, NULL, bh->b_data +
atomic_read(&bh->b_count), count);
bcount -= count;
atomic_add(count, &bh->b_count);
if (atomic_read(&bh->b_count) == bh->b_size) {
bh = bh->b_reqnext;
if (bh)
atomic_set(&bh->b_count, 0);
}
}
pc->bh = bh;
}
static void idetape_output_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
unsigned int bcount)
{
struct idetape_bh *bh = pc->bh;
int count;
while (bcount) {
if (bh == NULL) {
printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
__func__);
return;
}
count = min((unsigned int)pc->b_count, (unsigned int)bcount);
drive->hwif->tp_ops->output_data(drive, NULL, pc->b_data, count);
bcount -= count;
pc->b_data += count;
pc->b_count -= count;
if (!pc->b_count) {
bh = bh->b_reqnext;
pc->bh = bh;
if (bh) {
pc->b_data = bh->b_data;
pc->b_count = atomic_read(&bh->b_count);
}
}
}
}
static void idetape_update_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc)
{
struct idetape_bh *bh = pc->bh;
int count;
unsigned int bcount = pc->xferred;
if (pc->flags & PC_FLAG_WRITING)
return;
while (bcount) {
if (bh == NULL) {
printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
__func__);
return;
}
count = min((unsigned int)bh->b_size, (unsigned int)bcount);
atomic_set(&bh->b_count, count);
if (atomic_read(&bh->b_count) == bh->b_size)
bh = bh->b_reqnext;
bcount -= count;
}
pc->bh = bh;
}
/*
* called on each failed packet command retry to analyze the request sense. We
* currently do not utilize this information.
*/
static void idetape_analyze_error(ide_drive_t *drive, u8 *sense)
{
idetape_tape_t *tape = drive->driver_data;
struct ide_atapi_pc *pc = tape->failed_pc;
tape->sense_key = sense[2] & 0xF;
tape->asc = sense[12];
tape->ascq = sense[13];
debug_log(DBG_ERR, "pc = %x, sense key = %x, asc = %x, ascq = %x\n",
pc->c[0], tape->sense_key, tape->asc, tape->ascq);
/* Correct pc->xferred by asking the tape. */
if (pc->flags & PC_FLAG_DMA_ERROR) {
pc->xferred = pc->req_xfer -
tape->blk_size *
get_unaligned_be32(&sense[3]);
idetape_update_buffers(drive, pc);
}
/*
* If error was the result of a zero-length read or write command,
* with sense key=5, asc=0x22, ascq=0, let it slide. Some drives
* (i.e. Seagate STT3401A Travan) don't support 0-length read/writes.
*/
if ((pc->c[0] == READ_6 || pc->c[0] == WRITE_6)
/* length == 0 */
&& pc->c[4] == 0 && pc->c[3] == 0 && pc->c[2] == 0) {
if (tape->sense_key == 5) {
/* don't report an error, everything's ok */
pc->error = 0;
/* don't retry read/write */
pc->flags |= PC_FLAG_ABORT;
}
}
if (pc->c[0] == READ_6 && (sense[2] & 0x80)) {
pc->error = IDETAPE_ERROR_FILEMARK;
pc->flags |= PC_FLAG_ABORT;
}
if (pc->c[0] == WRITE_6) {
if ((sense[2] & 0x40) || (tape->sense_key == 0xd
&& tape->asc == 0x0 && tape->ascq == 0x2)) {
pc->error = IDETAPE_ERROR_EOD;
pc->flags |= PC_FLAG_ABORT;
}
}
if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
if (tape->sense_key == 8) {
pc->error = IDETAPE_ERROR_EOD;
pc->flags |= PC_FLAG_ABORT;
}
if (!(pc->flags & PC_FLAG_ABORT) &&
pc->xferred)
pc->retries = IDETAPE_MAX_PC_RETRIES + 1;
}
}
/* Free data buffers completely. */
static void ide_tape_kfree_buffer(idetape_tape_t *tape)
{
struct idetape_bh *prev_bh, *bh = tape->merge_bh;
while (bh) {
u32 size = bh->b_size;
while (size) {
unsigned int order = fls(size >> PAGE_SHIFT)-1;
if (bh->b_data)
free_pages((unsigned long)bh->b_data, order);
size &= (order-1);
bh->b_data += (1 << order) * PAGE_SIZE;
}
prev_bh = bh;
bh = bh->b_reqnext;
kfree(prev_bh);
}
}
static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects)
{
struct request *rq = drive->hwif->rq;
idetape_tape_t *tape = drive->driver_data;
unsigned long flags;
int error;
debug_log(DBG_PROCS, "Enter %s\n", __func__);
switch (uptodate) {
case 0: error = IDETAPE_ERROR_GENERAL; break;
case 1: error = 0; break;
default: error = uptodate;
}
rq->errors = error;
if (error)
tape->failed_pc = NULL;
if (!blk_special_request(rq)) {
ide_end_request(drive, uptodate, nr_sects);
return 0;
}
spin_lock_irqsave(&tape->lock, flags);
ide_end_drive_cmd(drive, 0, 0);
spin_unlock_irqrestore(&tape->lock, flags);
return 0;
}
static void ide_tape_handle_dsc(ide_drive_t *);
static void ide_tape_callback(ide_drive_t *drive, int dsc)
{
idetape_tape_t *tape = drive->driver_data;
struct ide_atapi_pc *pc = drive->pc;
int uptodate = pc->error ? 0 : 1;
debug_log(DBG_PROCS, "Enter %s\n", __func__);
if (dsc)
ide_tape_handle_dsc(drive);
if (tape->failed_pc == pc)
tape->failed_pc = NULL;
if (pc->c[0] == REQUEST_SENSE) {
if (uptodate)
idetape_analyze_error(drive, pc->buf);
else
printk(KERN_ERR "ide-tape: Error in REQUEST SENSE "
"itself - Aborting request!\n");
} else if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
struct request *rq = drive->hwif->rq;
int blocks = pc->xferred / tape->blk_size;
tape->avg_size += blocks * tape->blk_size;
if (time_after_eq(jiffies, tape->avg_time + HZ)) {
tape->avg_speed = tape->avg_size * HZ /
(jiffies - tape->avg_time) / 1024;
tape->avg_size = 0;
tape->avg_time = jiffies;
}
tape->first_frame += blocks;
rq->current_nr_sectors -= blocks;
if (pc->error)
uptodate = pc->error;
} else if (pc->c[0] == READ_POSITION && uptodate) {
u8 *readpos = pc->buf;
debug_log(DBG_SENSE, "BOP - %s\n",
(readpos[0] & 0x80) ? "Yes" : "No");
debug_log(DBG_SENSE, "EOP - %s\n",
(readpos[0] & 0x40) ? "Yes" : "No");
if (readpos[0] & 0x4) {
printk(KERN_INFO "ide-tape: Block location is unknown"
"to the tape\n");
clear_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags);
uptodate = 0;
} else {
debug_log(DBG_SENSE, "Block Location - %u\n",
be32_to_cpup((__be32 *)&readpos[4]));
tape->partition = readpos[1];
tape->first_frame = be32_to_cpup((__be32 *)&readpos[4]);
set_bit(IDE_AFLAG_ADDRESS_VALID, &drive->atapi_flags);
}
}
idetape_end_request(drive, uptodate, 0);
}
/*
* Postpone the current request so that ide.c will be able to service requests
* from another device on the same port while we are polling for DSC.
*/
static void idetape_postpone_request(ide_drive_t *drive)
{
idetape_tape_t *tape = drive->driver_data;
debug_log(DBG_PROCS, "Enter %s\n", __func__);
tape->postponed_rq = drive->hwif->rq;
ide_stall_queue(drive, tape->dsc_poll_freq);
}
static void ide_tape_handle_dsc(ide_drive_t *drive)
{
idetape_tape_t *tape = drive->driver_data;
/* Media access command */
tape->dsc_polling_start = jiffies;
tape->dsc_poll_freq = IDETAPE_DSC_MA_FAST;
tape->dsc_timeout = jiffies + IDETAPE_DSC_MA_TIMEOUT;
/* Allow ide.c to handle other requests */
idetape_postpone_request(drive);
}
static int ide_tape_io_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
unsigned int bcount, int write)
{
if (write)
idetape_output_buffers(drive, pc, bcount);
else
idetape_input_buffers(drive, pc, bcount);
return bcount;
}
/*
* Packet Command Interface
*
* The current Packet Command is available in drive->pc, and will not change
* until we finish handling it. Each packet command is associated with a
* callback function that will be called when the command is finished.
*
* The handling will be done in three stages:
*
* 1. idetape_issue_pc will send the packet command to the drive, and will set
* the interrupt handler to ide_pc_intr.
*
* 2. On each interrupt, ide_pc_intr will be called. This step will be
* repeated until the device signals us that no more interrupts will be issued.
*
* 3. ATAPI Tape media access commands have immediate status with a delayed
* process. In case of a successful initiation of a media access packet command,
* the DSC bit will be set when the actual execution of the command is finished.
* Since the tape drive will not issue an interrupt, we have to poll for this
* event. In this case, we define the request as "low priority request" by
* setting rq_status to IDETAPE_RQ_POSTPONED, set a timer to poll for DSC and
* exit the driver.
*
* ide.c will then give higher priority to requests which originate from the
* other device, until will change rq_status to RQ_ACTIVE.
*
* 4. When the packet command is finished, it will be checked for errors.
*
* 5. In case an error was found, we queue a request sense packet command in
* front of the request queue and retry the operation up to
* IDETAPE_MAX_PC_RETRIES times.
*
* 6. In case no error was found, or we decided to give up and not to retry
* again, the callback function will be called and then we will handle the next
* request.
*/
static ide_startstop_t idetape_issue_pc(ide_drive_t *drive,
struct ide_atapi_pc *pc)
{
idetape_tape_t *tape = drive->driver_data;
if (drive->pc->c[0] == REQUEST_SENSE &&
pc->c[0] == REQUEST_SENSE) {
printk(KERN_ERR "ide-tape: possible ide-tape.c bug - "
"Two request sense in serial were issued\n");
}
if (tape->failed_pc == NULL && pc->c[0] != REQUEST_SENSE)
tape->failed_pc = pc;
/* Set the current packet command */
drive->pc = pc;
if (pc->retries > IDETAPE_MAX_PC_RETRIES ||
(pc->flags & PC_FLAG_ABORT)) {
/*
* We will "abort" retrying a packet command in case legitimate
* error code was received (crossing a filemark, or end of the
* media, for example).
*/
if (!(pc->flags & PC_FLAG_ABORT)) {
if (!(pc->c[0] == TEST_UNIT_READY &&
tape->sense_key == 2 && tape->asc == 4 &&
(tape->ascq == 1 || tape->ascq == 8))) {
printk(KERN_ERR "ide-tape: %s: I/O error, "
"pc = %2x, key = %2x, "
"asc = %2x, ascq = %2x\n",
tape->name, pc->c[0],
tape->sense_key, tape->asc,
tape->ascq);
}
/* Giving up */
pc->error = IDETAPE_ERROR_GENERAL;
}
tape->failed_pc = NULL;
drive->pc_callback(drive, 0);
return ide_stopped;
}
debug_log(DBG_SENSE, "Retry #%d, cmd = %02X\n", pc->retries, pc->c[0]);
pc->retries++;
return ide_issue_pc(drive);
}
/* A mode sense command is used to "sense" tape parameters. */
static void idetape_create_mode_sense_cmd(struct ide_atapi_pc *pc, u8 page_code)
{
ide_init_pc(pc);
pc->c[0] = MODE_SENSE;
if (page_code != IDETAPE_BLOCK_DESCRIPTOR)
/* DBD = 1 - Don't return block descriptors */
pc->c[1] = 8;
pc->c[2] = page_code;
/*
* Changed pc->c[3] to 0 (255 will at best return unused info).
*
* For SCSI this byte is defined as subpage instead of high byte
* of length and some IDE drives seem to interpret it this way
* and return an error when 255 is used.
*/
pc->c[3] = 0;
/* We will just discard data in that case */
pc->c[4] = 255;
if (page_code == IDETAPE_BLOCK_DESCRIPTOR)
pc->req_xfer = 12;
else if (page_code == IDETAPE_CAPABILITIES_PAGE)
pc->req_xfer = 24;
else
pc->req_xfer = 50;
}
static ide_startstop_t idetape_media_access_finished(ide_drive_t *drive)
{
ide_hwif_t *hwif = drive->hwif;
idetape_tape_t *tape = drive->driver_data;
struct ide_atapi_pc *pc = drive->pc;
u8 stat;
stat = hwif->tp_ops->read_status(hwif);
if (stat & ATA_DSC) {
if (stat & ATA_ERR) {
/* Error detected */
if (pc->c[0] != TEST_UNIT_READY)
printk(KERN_ERR "ide-tape: %s: I/O error, ",
tape->name);
/* Retry operation */
ide_retry_pc(drive, tape->disk);
return ide_stopped;
}
pc->error = 0;
} else {
pc->error = IDETAPE_ERROR_GENERAL;
tape->failed_pc = NULL;
}
drive->pc_callback(drive, 0);
return ide_stopped;
}
static void ide_tape_create_rw_cmd(idetape_tape_t *tape,
struct ide_atapi_pc *pc, struct request *rq,
u8 opcode)
{
struct idetape_bh *bh = (struct idetape_bh *)rq->special;
unsigned int length = rq->current_nr_sectors;
ide_init_pc(pc);
put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
pc->c[1] = 1;
pc->bh = bh;
pc->buf = NULL;
pc->buf_size = length * tape->blk_size;
pc->req_xfer = pc->buf_size;
if (pc->req_xfer == tape->buffer_size)
pc->flags |= PC_FLAG_DMA_OK;
if (opcode == READ_6) {
pc->c[0] = READ_6;
atomic_set(&bh->b_count, 0);
} else if (opcode == WRITE_6) {
pc->c[0] = WRITE_6;
pc->flags |= PC_FLAG_WRITING;
pc->b_data = bh->b_data;
pc->b_count = atomic_read(&bh->b_count);
}
memcpy(rq->cmd, pc->c, 12);
}
static ide_startstop_t idetape_do_request(ide_drive_t *drive,
struct request *rq, sector_t block)
{
ide_hwif_t *hwif = drive->hwif;
idetape_tape_t *tape = drive->driver_data;
struct ide_atapi_pc *pc = NULL;
struct request *postponed_rq = tape->postponed_rq;
u8 stat;
debug_log(DBG_SENSE, "sector: %llu, nr_sectors: %lu,"
" current_nr_sectors: %u\n",
(unsigned long long)rq->sector, rq->nr_sectors,
rq->current_nr_sectors);
if (!blk_special_request(rq)) {
/* We do not support buffer cache originated requests. */
printk(KERN_NOTICE "ide-tape: %s: Unsupported request in "
"request queue (%d)\n", drive->name, rq->cmd_type);
ide_end_request(drive, 0, 0);
return ide_stopped;
}
/* Retry a failed packet command */
if (tape->failed_pc && drive->pc->c[0] == REQUEST_SENSE) {
pc = tape->failed_pc;
goto out;
}
if (postponed_rq != NULL)
if (rq != postponed_rq) {
printk(KERN_ERR "ide-tape: ide-tape.c bug - "
"Two DSC requests were queued\n");
idetape_end_request(drive, 0, 0);
return ide_stopped;
}
tape->postponed_rq = NULL;
/*
* If the tape is still busy, postpone our request and service
* the other device meanwhile.
*/
stat = hwif->tp_ops->read_status(hwif);
if ((drive->dev_flags & IDE_DFLAG_DSC_OVERLAP) == 0 &&
(rq->cmd[13] & REQ_IDETAPE_PC2) == 0)
set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
if (drive->dev_flags & IDE_DFLAG_POST_RESET) {
set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
drive->dev_flags &= ~IDE_DFLAG_POST_RESET;
}
if (!test_and_clear_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags) &&
(stat & ATA_DSC) == 0) {
if (postponed_rq == NULL) {
tape->dsc_polling_start = jiffies;
tape->dsc_poll_freq = tape->best_dsc_rw_freq;
tape->dsc_timeout = jiffies + IDETAPE_DSC_RW_TIMEOUT;
} else if (time_after(jiffies, tape->dsc_timeout)) {
printk(KERN_ERR "ide-tape: %s: DSC timeout\n",
tape->name);
if (rq->cmd[13] & REQ_IDETAPE_PC2) {
idetape_media_access_finished(drive);
return ide_stopped;
} else {
return ide_do_reset(drive);
}
} else if (time_after(jiffies,
tape->dsc_polling_start +
IDETAPE_DSC_MA_THRESHOLD))
tape->dsc_poll_freq = IDETAPE_DSC_MA_SLOW;
idetape_postpone_request(drive);
return ide_stopped;
}
if (rq->cmd[13] & REQ_IDETAPE_READ) {
pc = &tape->queued_pc;
ide_tape_create_rw_cmd(tape, pc, rq, READ_6);
goto out;
}
if (rq->cmd[13] & REQ_IDETAPE_WRITE) {
pc = &tape->queued_pc;
ide_tape_create_rw_cmd(tape, pc, rq, WRITE_6);
goto out;
}
if (rq->cmd[13] & REQ_IDETAPE_PC1) {
pc = (struct ide_atapi_pc *) rq->buffer;
rq->cmd[13] &= ~(REQ_IDETAPE_PC1);
rq->cmd[13] |= REQ_IDETAPE_PC2;
goto out;
}
if (rq->cmd[13] & REQ_IDETAPE_PC2) {
idetape_media_access_finished(drive);
return ide_stopped;
}
BUG();
out:
return idetape_issue_pc(drive, pc);
}
/*
* The function below uses __get_free_pages to allocate a data buffer of size
* tape->buffer_size (or a bit more). We attempt to combine sequential pages as
* much as possible.
*
* It returns a pointer to the newly allocated buffer, or NULL in case of
* failure.
*/
static struct idetape_bh *ide_tape_kmalloc_buffer(idetape_tape_t *tape,
int full, int clear)
{
struct idetape_bh *prev_bh, *bh, *merge_bh;
int pages = tape->pages_per_buffer;
unsigned int order, b_allocd;
char *b_data = NULL;
merge_bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
bh = merge_bh;
if (bh == NULL)
goto abort;
order = fls(pages) - 1;
bh->b_data = (char *) __get_free_pages(GFP_KERNEL, order);
if (!bh->b_data)
goto abort;
b_allocd = (1 << order) * PAGE_SIZE;
pages &= (order-1);
if (clear)
memset(bh->b_data, 0, b_allocd);
bh->b_reqnext = NULL;
bh->b_size = b_allocd;
atomic_set(&bh->b_count, full ? bh->b_size : 0);
while (pages) {
order = fls(pages) - 1;
b_data = (char *) __get_free_pages(GFP_KERNEL, order);
if (!b_data)
goto abort;
b_allocd = (1 << order) * PAGE_SIZE;
if (clear)
memset(b_data, 0, b_allocd);
/* newly allocated page frames below buffer header or ...*/
if (bh->b_data == b_data + b_allocd) {
bh->b_size += b_allocd;
bh->b_data -= b_allocd;
if (full)
atomic_add(b_allocd, &bh->b_count);
continue;
}
/* they are above the header */
if (b_data == bh->b_data + bh->b_size) {
bh->b_size += b_allocd;
if (full)
atomic_add(b_allocd, &bh->b_count);
continue;
}
prev_bh = bh;
bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
if (!bh) {
free_pages((unsigned long) b_data, order);
goto abort;
}
bh->b_reqnext = NULL;
bh->b_data = b_data;
bh->b_size = b_allocd;
atomic_set(&bh->b_count, full ? bh->b_size : 0);
prev_bh->b_reqnext = bh;
pages &= (order-1);
}
bh->b_size -= tape->excess_bh_size;
if (full)
atomic_sub(tape->excess_bh_size, &bh->b_count);
return merge_bh;
abort:
ide_tape_kfree_buffer(tape);
return NULL;
}
static int idetape_copy_stage_from_user(idetape_tape_t *tape,
const char __user *buf, int n)
{
struct idetape_bh *bh = tape->bh;
int count;
int ret = 0;
while (n) {
if (bh == NULL) {
printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
__func__);
return 1;
}
count = min((unsigned int)
(bh->b_size - atomic_read(&bh->b_count)),
(unsigned int)n);
if (copy_from_user(bh->b_data + atomic_read(&bh->b_count), buf,
count))
ret = 1;
n -= count;
atomic_add(count, &bh->b_count);
buf += count;
if (atomic_read(&bh->b_count) == bh->b_size) {
bh = bh->b_reqnext;
if (bh)
atomic_set(&bh->b_count, 0);
}
}
tape->bh = bh;
return ret;
}